Struct lightning::chain::channelmonitor::ChannelMonitor

pub struct ChannelMonitor<Signer: Sign> { /* fields omitted */ }

A ChannelMonitor handles chain events (blocks connected and disconnected) and generates on-chain transactions to ensure no loss of funds occurs.

You MUST ensure that no ChannelMonitors for a given channel anywhere contain out-of-date information and are actively monitoring the chain.

Pending Events or updated HTLCs which have not yet been read out by get_and_clear_pending_monitor_events or get_and_clear_pending_events are serialized to disk and reloaded at deserialize-time. Thus, you must ensure that, when handling events, all events gotten are fully handled before re-serializing the new state.

Note that the deserializer is only implemented for (BlockHash, ChannelMonitor), which tells you the last block hash which was block_connect()ed. You MUST rescan any blocks along the “reorg path” (ie disconnecting blocks until you find a common ancestor from both the returned block hash and the the current chain and then reconnecting blocks to get to the best chain) upon deserializing the object!

Implementations

impl<Signer: Sign> ChannelMonitor<Signer>

pub fn update_monitor<B: Deref, F: Deref, L: Deref>(
    &self,
    updates: &ChannelMonitorUpdate,
    broadcaster: &B,
    fee_estimator: &F,
    logger: &L
) -> Result<(), MonitorUpdateError> where
    B::Target: BroadcasterInterface,
    F::Target: FeeEstimator,
    L::Target: Logger, 

Updates a ChannelMonitor on the basis of some new information provided by the Channel itself.

panics if the given update is not the next update by update_id.

pub fn get_latest_update_id(&self) -> u64

Gets the update_id from the latest ChannelMonitorUpdate which was applied to this ChannelMonitor.

pub fn get_funding_txo(&self) -> (OutPoint, Script)

Gets the funding transaction outpoint of the channel this ChannelMonitor is monitoring for.

pub fn get_outputs_to_watch(&self) -> Vec<(Txid, Vec<(u32, Script)>)>

Gets a list of txids, with their output scripts (in the order they appear in the transaction), which we must learn about spends of via block_connected().

pub fn load_outputs_to_watch<F: Deref>(&self, filter: &F) where
    F::Target: Filter, 

Loads the funding txo and outputs to watch into the given chain::Filter by repeatedly calling chain::Filter::register_output and chain::Filter::register_tx until all outputs have been registered.

pub fn get_and_clear_pending_monitor_events(&self) -> Vec<MonitorEvent>

Get the list of HTLCs who’s status has been updated on chain. This should be called by ChannelManager via chain::Watch::release_pending_monitor_events.

pub fn get_and_clear_pending_events(&self) -> Vec<Event>

Gets the list of pending events which were generated by previous actions, clearing the list in the process.

This is called by ChainMonitor::get_and_clear_pending_events() and is equivalent to EventsProvider::get_and_clear_pending_events() except that it requires &mut self as we do no internal locking in ChannelMonitors.

pub fn get_latest_holder_commitment_txn<L: Deref>(
    &self,
    logger: &L
) -> Vec<Transaction> where
    L::Target: Logger, 

Used by ChannelManager deserialization to broadcast the latest holder state if its copy of the Channel was out-of-date. You may use it to get a broadcastable holder toxic tx in case of fallen-behind, i.e when receiving a channel_reestablish with a proof that our counterparty side knows a higher revocation secret than the holder commitment number we are aware of. Broadcasting these transactions are UNSAFE, as they allow counterparty side to punish you. Nevertheless you may want to broadcast them if counterparty don’t close channel with his higher commitment transaction after a substantial amount of time (a month or even a year) to get back funds. Best may be to contact out-of-band the other node operator to coordinate with him if option is available to you. In any-case, choice is up to the user.

pub fn block_connected<B: Deref, F: Deref, L: Deref>(
    &self,
    header: &BlockHeader,
    txdata: &TransactionData<'_>,
    height: u32,
    broadcaster: B,
    fee_estimator: F,
    logger: L
) -> Vec<TransactionOutputs> where
    B::Target: BroadcasterInterface,
    F::Target: FeeEstimator,
    L::Target: Logger, 

Processes transactions in a newly connected block, which may result in any of the following:

• update the monitor’s state against resolved HTLCs
• punish the counterparty in the case of seeing a revoked commitment transaction
• force close the channel and claim/timeout incoming/outgoing HTLCs if near expiration
• detect settled outputs for later spending
• schedule and bump any in-flight claims

Returns any new outputs to watch from txdata; after called, these are also included in get_outputs_to_watch.

pub fn block_disconnected<B: Deref, F: Deref, L: Deref>(
    &self,
    header: &BlockHeader,
    height: u32,
    broadcaster: B,
    fee_estimator: F,
    logger: L
) where
    B::Target: BroadcasterInterface,
    F::Target: FeeEstimator,
    L::Target: Logger, 

Determines if the disconnected block contained any transactions of interest and updates appropriately.

pub fn transactions_confirmed<B: Deref, F: Deref, L: Deref>(
    &self,
    header: &BlockHeader,
    txdata: &TransactionData<'_>,
    height: u32,
    broadcaster: B,
    fee_estimator: F,
    logger: L
) -> Vec<TransactionOutputs> where
    B::Target: BroadcasterInterface,
    F::Target: FeeEstimator,
    L::Target: Logger, 

Processes transactions confirmed in a block with the given header and height, returning new outputs to watch. See block_connected for details.

Used instead of block_connected by clients that are notified of transactions rather than blocks. See chain::Confirm for calling expectations.

pub fn transaction_unconfirmed<B: Deref, F: Deref, L: Deref>(
    &self,
    txid: &Txid,
    broadcaster: B,
    fee_estimator: F,
    logger: L
) where
    B::Target: BroadcasterInterface,
    F::Target: FeeEstimator,
    L::Target: Logger, 

Processes a transaction that was reorganized out of the chain.

Used instead of block_disconnected by clients that are notified of transactions rather than blocks. See chain::Confirm for calling expectations.

pub fn best_block_updated<B: Deref, F: Deref, L: Deref>(
    &self,
    header: &BlockHeader,
    height: u32,
    broadcaster: B,
    fee_estimator: F,
    logger: L
) -> Vec<TransactionOutputs> where
    B::Target: BroadcasterInterface,
    F::Target: FeeEstimator,
    L::Target: Logger, 

Updates the monitor with the current best chain tip, returning new outputs to watch. See block_connected for details.

Used instead of block_connected by clients that are notified of transactions rather than blocks. See chain::Confirm for calling expectations.

pub fn get_relevant_txids(&self) -> Vec<Txid>

Returns the set of txids that should be monitored for re-organization out of the chain.

pub fn current_best_block(&self) -> BestBlock

Gets the latest best block which was connected either via the chain::Listen or chain::Confirm interfaces.

Trait Implementations

impl<Signer: Sign> Writeable for ChannelMonitor<Signer>

fn write<W: Writer>(&self, writer: &mut W) -> Result<(), Error>

Writes self out to the given Writer

fn encode(&self) -> Vec<u8>

Writes self out to a Vec

fn encode_with_len(&self) -> Vec<u8>

Writes self out to a Vec

fn serialized_length(&self) -> usize

Gets the length of this object after it has been serialized. This can be overridden to optimize cases where we prepend an object with its length.